1. Field of Invention
The invention relates to LED (light-emitting diode) lighting devices and more particularly such an LED lighting device (e.g., street light) having an improved heat dissipation arrangement.
2. Description of Related Art
LEDs are renowned for their long life and their ability to resist shock. Also, an LED consumes much less electrical power than fluorescent lamps (i.e., energy saving). Therefore, LED lighting devices are gaining popularity worldwide.
Recently, LEDs as a light source have been employed in outdoor lighting devices (e.g., street lights). Typically, heat dissipation is an important issue to be addressed in the manufacturing of an LED lamp because LED elements are sensitive to temperature conditions.
One conventional LED lamp has a metal globe for concealing LEDs. However, the heat dissipation performance of the LED lamp is poor because the globe is not in contact with the LEDs and natural air ventilation is blocked by the globe.
Another conventional LED lamp as an improvement of the above LED lamp has plurality of fins mounted on a lamp casing. Heat generated by LEDs can be discharged through the fins. However, it is a one way heat dissipation path. Hence, its heat dissipation performance is still low. Further, the exposed fins are visually unattractive (i.e., ugly). Furthermore, the globe and the fins, made of aluminum or alloy thereof due to the consideration of cost reduction, are inferior to ones made of copper in terms of heat conduction performance.
There have been numerous suggestions in prior patents for LED lighting device. For example, U.S. Pat. No. 6,942,361 discloses a light source for white color LED lighting and white color LED lighting device. Thus, continuing improvements in the exploitation of LED lighting device having an improved heat dissipation arrangement are constantly being sought.